Amorphous CuSbO_x composite-catalyzed electrocatalytic reduction of CO₂ to CO: CO₂ demand-supply-regulated performance

The path to practical production of targeted chemicals and fuels application via carbon dioxide reduction reactions (CO₂RRs) remains a significant challenge mainly due to low CO₂ solubility. Aiming to tackle this key issue, herein, we used the CuSbO_x cathode-catalyzed reduction of CO₂ to CO as a model system to quantitatively depict CO₂ demand-supply and performance relationships. We propose a cathode/electrolyte interface model consisting of a porous catalyst layer, and we combined the experimental and computational COMSOL Multiphysics finite-element studies to quantitatively unveil CO₂ demand-supply relationships and determine the maximum CO₂ supply capacity in both stationary H cell and gas diffusion electrode (GDE) flow cell. This work exemplifies that experimentally measured catalytic performance may not accurately reflect the maximum capacity/intrinsic electrocatalytic activity of electrocatalysts and reveals that CO₂ supply capacity in the GDE flow cell can be dramatically affected by the thickness of the liquid layer between the hydrophobic gas diffusion layer and the catalyst layer.